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https://issues.apache.org/jira/browse/CASSANDRA-5552?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jonathan Ellis resolved CASSANDRA-5552.
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Resolution: Duplicate
> Cassandra doesn't preload key caches from disk on start
> -------------------------------------------------------
>
> Key: CASSANDRA-5552
> URL: https://issues.apache.org/jira/browse/CASSANDRA-5552
> Project: Cassandra
> Issue Type: Bug
> Components: Core
> Affects Versions: 1.1.9
> Environment: CentOS 6.2, Datastax Cassandra Commutnity Edition package
> Reporter: Alexey Plotnik
> Labels: performance
>
> My cache related settings is default:
> {quote}
> key_cache_size_in_mb: # no value here
> key_cache_save_period: 14400
> row_cache_size_in_mb: 0
> row_cache_save_period: 0
> row_cache_provider: SerializingCacheProvider
> saved_caches_directory: /var/opt/cassandra/data/saved_caches
> {quote}
> Every time I restart Cassandra node with *service cassandra stop; service
> cassandra start* commands I see with Zabbix or JMX or *nodetool info* the key
> cache has been nulled. It happens every time I restart the node. This
> situation is stable on all the nodes of the cluster. I guessed since the key
> cache is flushed to disk every 4 hours I should never see the situation with
> cold caches.
> The output of *nodetool info* after 30 minutes from node has been started:
> bq.Key Cache : size 2105664 (bytes), capacity 104857584 (bytes), 3812
> hits, 47610 requests, 0.371 recent hit rate, 14400 save period in seconds
> Before restarting it looked as follows:
> bq.Key Cache : size 104857584 (bytes), capacity 104857584 (bytes),
> 79777150 hits, 502884072 requests, 0.847 recent hit rate, 14400 save period
> in seconds
> All the nodes have the cache capacity auto-calculated to 104857584 (100 Mb)
> according to settings I put above.
> The capacity of saved_caches directory on all the nodes is strange: with
> command
> bq.ansible cassandra -i hosts -m raw -a 'du -s
> /var/opt/cassandra/data/saved_caches' | grep caches
> I see values from 50 to 100 Kb only, against the values of 100Mb the
> `nodetool info` outputs.
> After node restart in 1 week the key cache is filled up to ~2,2 million of
> keys, but when I perform node restart (after running for few days) it is
> nulled again.
> I've never changed the default configuration of cassandra caches. What's
> going wrong? Thanks.
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